Impact of activation on properties of carbon-based solid acid catalysts for the hydrothermal conversion of xylose and hemicelluloses
Impact of activation on properties of carbon-based solid acid catalysts for the hydrothermal conversion of xylose and hemicelluloses
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DOI：
10.1016/j.cattod.2018.03.070
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发表时间：
2019-01-01
期刊：
影响因子：
5.3
通讯作者：
Ren, Jun-li
中科院分区：
文献类型：
--
作者：
Lin, Qi-xuan;Zhang, Chun-hui;Ren, Jun-li
活化对炭材料孔结构的改善起着重要作用。对于碳基固体催化剂，活化可以提供高的比表面积和孔隙率。本论文以木糖和半纤维素为原料，采用非活化、KOH活化、ZnCl 2活化三种方法制备碳基固体酸催化剂，并对催化剂的制备工艺进行了研究。采用SEM、FT-IR、元素分析、拉曼、N-2吸附-脱附和Boehm滴定等手段对催化剂进行了表征。结果表明，化学活化处理能显著提高炭基固体催化剂的比表面积，但对催化剂表面官能团的分布也有重要影响，尤其是降低了-SO 3 H密度，提高了酚基-OH和-COOH密度。对于-SO 3 H浓度最高的非活性炭基催化剂，其在木糖转化为糠醛的反应中表现出比其他催化剂更高的催化活性。同时，在水溶液中使用非活性炭基催化剂，在200 ℃下反应2.5 h，半纤维素的糠醛产率最高可达50%，木糖产率最高可达55%。KOH活性炭基催化剂在180 ℃反应1.5h时，低聚木糖的产率最高，为62%。
Activation plays an important role in improving the pore structure of the carbon materials preparation. For carbon-based solid catalysts, activation could provide the high specific surface area and porosity. In this work, non-activated, KOH-activated, ZnCl2-activated treatments were comparatively discussed to prepare carbon-based solid acid catalysts for furfural production from xylose and hemicelluloses. These prepared catalysts were characterized by SEM, FT-IR, elemental analysis, Raman, N-2 adsorption-desorption and Boehm titration. The results showed that the chemical activated treatment could significantly improve the specific surface area of carbon-based solid catalysts, but also had an important influence on the distribution of surface functional groups especially for decreasing of the -SO3H density and the enhancement of the phenolic -OH and -COOH density. For the highest -SO3H density of non-activated carbon-based catalyst, it displayed higher catalytic activity in the conversion of xylose to furfural than other catalysts. Meanwhile, using non-activated carbon-based catalyst in the aqueous solution, the maximum furfural yield of 50% was obtained from hemicelluloses at 200 degrees C for 2.5 h, the maximum xylose yield of 55% was achieved at 200 degrees C for 1.5 h. While KOH-activated carbon-based catalyst exhibited the excellent catalytic performance to produce xylooligosaccharide with the highest yield of 62% at 180 degrees C for 1.5 h.